Combustion machines

ABSTRACT

The invention relates to an apparatus on and a method by internal combustion machines with a device for continually measuring the amount of incoming combustion air and a device for measuring and uniformly distributing the amounts of a fuel corresponding to the amount of air to a plurality of injection valves associated with a plurality of operating cylinders. An adjustable valve plate is arranged in an air inlet channel upon which the combustion air and restoring means exert from opposite direction which move the valve plate into an equilibrium position. The movement of the valve plate is arranged to alter a throughput opening in a fuel control line (which comes from the pump via a resistance with laminar flow characteristic and recircles completely back to the tank via a difference pressure regulator) by means of a control member in proportion to the amount of air flowing in the combustion air channel. The flow through the throughput opening produces in accordance with the width of this opening a fuel control pressure in the fuel control line conveying a fuel control flow. The fuel control pressure actuates (or steers towards) a plurality of pressure regulators connected in parallel and associated with the respective injection valve, through which the fuel passes in a special fuel line via measuring resistances of laminar flow characteristic for injection and in which the outflow cross-section is adjusted in dependence upon the fuel control pressure so that the pressure drop at the measuring resistance of each pressure regulator is equal to the pressure drop at the amplifying resistance. The apparatus is accomplished by a series of additional embodiments (7a; 77 and 79; 71, 81 and 83, 89 and 91) with which the exact proportional measuring may be altered in cases of special requirements, that is e.g. cold start and full load.

United States Patent [1 1 Zeyns et a1.

[ 11 Feb. 25, 1975 COMBUSTION MACHINES [76] Inventors: Johannes Zeyns, Krauler Elbdeich,

Pappelhof, 2 Hamburg-Kirchwerder 4; Heinz Enneking, l-legholt 32, 2 Hamburg, both of Germany 22 Filed: .luly30, 1972 [21] App]. No.: 268,656

[30] Foreign Application Priority Data July 9, 1971 Germany 2134203 Dec. 15, 1971 Germany 2162241 [52] 11.8. C1 123/119 R, 123/139 AW [51] int. Cl. F02d 3/00 [58] Field of Search 123/119 R, 139 AW; 261/50 A [56] References Cited UNITED STATES PATENTS 3,589,384 6/1971 Eckert 123/139 AW 3,680,535 8/1972 Eckert et al. 123/119 R 3,703,888 11/1972 Eckert et a1. 123/119 R Primary Examiner-Wendell E. Burns Attorney, Agent, or Firm-Edwin E. Greigg [5 7] ABSTRACT The invention relates to an apparatus on and a method by internal combustion machines with a device for continually measuring the amount of incoming com bustion air and a device for measuring and uniformly distributing the amounts of a fuel corresponding to the amount of air to a plurality of injection valves associated with a plurality of operating cylinders. An adjustable valve plate is arranged in an air inlet channel upon which the combustion air and restoring means exert from opposite direction which move the valve plate into an equilibrium position. The movement of the valve plate is arranged to alter a throughput opening in a fuel control line (which comes from the pump via a resistance with laminar flow characteristic and recircles completely back to the tank via a difference pressure regulator) by means of a control member in proportion to the amount of air flowing in the combustion air channel. The flow through the throughput opening produces in accordance with the width of this opening a fuel control pressure in the fuel control line conveying a fuel control flow. The fuel control pressure actuates (or steers towards) a plurality of pres sure regulators connected in parallel and associated with the respective injection valve, through which the fuel passes in a special fuel line via measuring resistances of laminar flow characteristic for injection and in which the outflow cross-section is adjusted in dependence upon the fuel control pressure so that the pressure drop at the measuring resistance of each pressure regulator is equal to the pressure drop at the amplifying resistancev The apparatus is accomplished by a series of additional embodiments (7a; 77 and 79; 71, 81 and 83, 89 and 91) with which the exact proportional measuring may be altered in cases of special requirements, that is e.g. cold start and full load.

22 Claims, 6 Drawing Figures FAIEMIEB FIGA COMBUSTION MACHINES BACKGROUND OF THE INVENTION Field of Invention and Prior Art The invention relates to an apparatus on combustion machines with a device for continually measuring the amount of combustion air drawn in and for proportioning and uniformly distributing the amounts of fuel to be supplied the amounts of combustion air in a plurality of injection valves associated with a plurality of operating cylinders, wherein an adjustable valve plate is arranged in the air inlet channel, upon which the combustion air and a restoring member exert opposing forces from contrary directions, which shift the valve plate into an equilibrium position.

To avoid environmental pollution by combustion engine machines, particularly Otto engines, it is necessary to supply an optimum fuel/air mixture to each cylinder. This is effected by measuring the air inlet flow and, so far as is possible, supplying the correct amount of fuel to each cylinder in dependence thereon. An apparatus used for this purpose is described in German Gebrauchsmuster Specification No. 6946457. The apparatus according to this specification contains a relatively heavy pivoted lever which is mounted at its center of gravity. The pivoted lever undergoes rocking motion, during operation of an engine, due to the loss of equilibrium of the moments, this motion upsets measurement of the fuel. Also, the speed of movement and return deteriorates, because of the large mass carried by the pivoted lever.

The distribution of the amounts to the separate cylinders is effected in this apparatus by means of a control member which is mechanically coupled with the lever. The disadvantage connected with this is that the air measuring apparatus cannot be spatially separated from the fuel distributing device. Consequently, this unit is so large that it cannot be incorporated at all or only with difficulty in the engine of many vehicles, because of the constricted space in the inlet channel.

Moreover, it can be very disadvantageous that the fuel supplied from the fuel pump must first flow to this compact unit, in order to be distributed there and then to be passed via separate linesto the injection valves. Having regard to safety against fire during a collision and for the space reasons mentioned, it is very desirable to carry out distribution of the fuel at spaced wellprotected places by means of very short fuel lines.

Distribution of the fuel, particularly during idling, requires extremely high precision, with four parallel control slots according to the Gebrauchsmuster, since because of the translatory movement of the pivot lever, the stroke of the control member is small and consequently the control path in idling is extremely small. Still more onerous are the requirements with increasing numbers of control slots with six and eight cylinder machines, for exactly as with the four parallel control slots, the fuel must always be supplied under a constant pressure. The requirements for manufacturing precision and the many fuel lines, which do not comply with fire safety standards, make the apparatus known from the German Gebrauchsmuster commercially impractical because of the weight-carrying pivotted lever, quite apart from the unsafe operating characteristics.

Furthermore, an air measuring device for a carburetter is described in U.S. Pat. No. 2,591,356. This device again operates with a valve plate arranged on a pivot lever. The restoring force acting on the pivot lever and the valve plate is produced by a spring, in addition to the hydraulic restoring force according to the Gebrauchsmuster, namely, in such a way that, with increasing air throughput, both the spring force and the hydraulic force are increased and are additive. ln this way, no constant sensitivity over the whole range of operation can be achieved. Clearly, this unsatisfactory adjustment of forces in the device according to the U.S. patent specification is necessary for valves with a completely predetermined operative characteristic. The valves cannot operate independently of one another.

In German published Patent Specification 1,291,934, a regulating device for measuring the fuel to be injected into a combustion machine is described, according to which a regulating pressure is derived from a venturi tube and is amplified by means of a piston arranged in a compression cylinder. By means of this amplified pressure, the fuel is injected in. This device has the disadvantage that the pressures on the measuring side and on the injection side differ, because of the quadratic law of the dependence of pressure upon throughput, by a factor of the order of 1,000. Since this range is not technically controllable, a separate idling jet for measuring the fuel is required, which takes over the measurement in the non-controllable lower range of rate of revolution. Consequently, in this device, uniform distribution to the separate injection valves is not ensured.

The known devices thus have quite specific disadvantages which, because of the operation of different injection valves with different operating characteristics, manufacturing tolerances and fuel safety requirements, cannot be overcome in the way described.

DESCRIPTION AND OBJECTS OF THE INVENTION It is an object of the invention to provide a device which, in one apparatus, enables the use of injection valves of different characteristics with modest manufacturing requirements and also enables distribution of the fuel to the separate injection valves spatially independently of the air metering equipment.

This object is achieved in an apparatus of the kind mentioned initially in that, according to the invention, the valve plate, in its movements, alters by means of a control member the throughput cross-section of an inlet opening in a fuel control line proportionally to the amounts of air flowing in the combustion air channel, whereby a fuel control pressure is established in a fuel control line leading upstream via an amplifying resistance to the fuel pump, forming a fuel control supply or flow and leading downstream via a pressure difference regulator back to the tank behind (downstream) of the amplifier resistance, which fuel control pressure actuates a plurality of equal pressure regulators separately connected in parallel to the associated injection valves, through which regulators fuel flows by way of measurement resistances for injection and in which the outflow cross-section is adjusted in dependence upon the fuel control pressure such that the pressure drop at the measurement resistance of each equal pressure reg ulator is equal to the pressure drop at the amplifying resistance.

Because of the compensatory connection of the control and measurement flows via the amplifying and measuring resistances, insensitivity to variations in the viscosity of fuel is guaranteed.

Each adjustment of the control flow automatically causes a corresponding adjustment of all fuel injection flows.

In order to obtain a structurally compact air measuring device, the valve plate can be arranged directly on the control member. Because of the low mass and low inertia forces, the speed of adjustment is thus increased considerably. The throughput opening is provided in a control cylinder in which the valve plate moves a control member provided with an annular groove, one wall of the annular groove serving as the control edge determining the throughput cross-section.

In order to ensure a sufficiently large operative capacity of the control device, the stroke of the pistonlike control member is adapted to the stroke of the valve plate. In order that this adjustment does not make necessary too small a control slot, with which the risk of clogging would arise, the fuel flow is considerably increased through the control slot. This is directly possible since the fuel through the control slot is not measured out to the individual inlet valves, but merely serves to produce a control pressure in order thus to actuate a spatially separate universely usable volume distribution device. The fuel required for control purposes is returned to the tank counte-rcurrently to the throughput opening.

The fuel delivered by the fuel pump is passed via an amplifying resistance to the control member which varies the extent of a throughput opening with rectangular cross-section. The pressure at the control member is thus not constant. It increases with increasing fuel flow through the throughput opening. The pressure difference between the input and the output at the throughput opening is kept substantially constant by means of the difference pressure regulator which, in principle, is a sensitive over-pressure valve. The resultant pressure different changes only in accordance with increases and decreases in the control puressure.

In such a device, by means of the pneumatically controlled hydraulic valve member with a rectangular stroke-proportional cross-section, an individual control flow is produced which is proportional to the magnitude of the air flow. The control member finds its equilibrium position in dependence upon the equilibrium of pneumatic and variable hydraulic forces or additional spring forces. The spring forces and pressure forces are so controlled that, with increasing air throughput, the hydraulic back-pressure decreases, whereas the spring pressure increases.

The magnitude of the control flow can be selected as required, since the amplifying resistance can be adapted at any time to the control flow. It is thus possible with a large stroke of the control member to make the control slot sufficiently wide that no clogging can occur. By this expedient, the manufacturing tolerances can fall by more than a power of ten while correspondingly maintaining measurement accuracy. Since a separate control flow is no longer necessary for each cylinder, but instead a common control flow, the usual requirements as to accuracy, which apply with parallel operating slots particularly during idling, can be dispensed with.

A number of pressure regulators corresponding to the number of cylinders is used for governing the separate cylinders. These pressure regulators themselves measure into the cylinders an exactly prescribed amount of fuel determined by the control pressure which ensures optimum combustion. This information transmitted by hydraulic pressures makes it possible to locate the various components in the most protected positions, so that if an accident occurs the risk of fire is reduced to a minimum, with simultaneously facilitated installation.

According to an advantageous embodiment of the invention, the fuel supplied from the control member at the throughput cross-section is passed into a first regulating chamber of the difference pressure regulator, which is separated by means of a membrane from a second regulating chamber which is under the control pressure. Further, from the side of the first regulating chamber a force acts against the membrane which determines the difference pressure between the regulating chambers, which difference pressure serves to determine the dimensions of the throughput crosssection. The force acting on the membrane can be provided by a spring. This spring thus itself gives the difference pressure between the feed lines before and after the control member.

According to a further feature of the invention, the fuel flowing into the first regulating chamber returns to the tank via an overpressure regulator. The overpressure regulator ensures that, in the exit line from the difference pressure regulator to the overpressure regulator, a continous pressure is maintained and that evaporation of the fuel in the whole apparatus is thus avoided.

According to a further advantageous feature of the invention, a fuel line is taken off upstream of the amplifying resistance which passes a part of the fuel supplied from the pump via an overflow valve to the first regulating chamber and thus allows an auxiliary compensating flow to pass to the overpressure regulator arranged in the return line to the tank. This auxiliary compensating flow has the advantage that the chamber is filled more rapidly on expansion. Moreover, temperature compensation is thus provided.

According to a further feature of the invention, a pressure space is provided in the control cylinder on the side away from the valve plate, which space is defined on the valve plate side by the end of the control member, and the pressure space is connected to one of the lines supplying fuel under pressure. If the difference pressure regulator is to be combined directly with the control member, the pressure space is connected to the constant fuel pressure supply line between the difference pressure regulator and the overpressure regulator. In this case, the end surface of the member can be so dimensioned that the hydraulic pressure on the end surface, which is substantially constant, corresponds to the constant air pressure on the valve plate. If it is desirable for various reasons for the difference pressure regulator to be located at another place, then the pressure space is connected to the fuel line upstream of the throughput opening. Since the control pressure at the exit side of the control member is not constant, this constancy is ensured by a spring which contacts the valve plate from the control member side. Spring pressure and hydraulic force are so predetermined in this case that they provide a substantially constant counterforce on the valve plate over the whole operating range.

According to a further feature of the invention, a fuel line is taken off upstream of the amplifying resistance and is connected in parallel with lines provided with measuring resistances leading to the neasuring chambers of equal pressure regulators. Since the measuring valves of the equal pressure regulator cannot affect the control flow and thus the control pressure in any way, any number of measuring valves can be connected in parallel, without the accuracy of measurement being adversely affected.

, In order to control the fuel supply on skidding, according to a further feature of the invention, a magnetic valve is arranged in the fuel supply line common to the equal pressure regulators and serving to control the injection valves.

When the magnetic valve closes, the fuel injection is cut off. The control flow is not altered, however, so that it operates without any delay effect on re-opening of the valve.

According to a further feature of the invention, the equal pressure regulator has a regulating chamber under the control pressure and the measuring chamber separated from this by means ofa membrane, in which a valve is located, which more or less opens or closes in dependence upon the yielding of the membrane which is determined by the control pressure.

The amplifier resistance and the measuring resistances consist of resistance elements with laminar flow, by which equal pressure drops for the fuel are produced. lf several equal pressure regulators are connected in parallel in which the fuel supply passes via the laminar measuring resistances to the outlet chambers, then the control pressure in the regulating chambers produces an increasing fuel throughput, if the control pressure drops. Conversely, if the fuel throughput falls, then the control pressure in the regulating chambers rises.

Since the air force is always constant because of the construction of the device according to the invention, as this force constantly opposes a constant counterforce, the variable control pressure produced in accordance with the magnitude of the air variation, thus produces a fuel amount which is exactly proportional to the amount of air.

Variations in the air/fuel mixture ratio in dependence upon the throughput can be controlled by additive, multiplicative and quadratic variations of one of these two flows. According to a further feature of the invention, a remotely-controllable stop valve is provided in the fuel control line upstream of the amplifying resistance, which valve is connected in parallel to a laminar resistance. I

By introducing the parallel connected laminar resistance, on closure of the valve in the fuel control line, which is constructed as an on/off valve, the control pressure in this line upstream of the pressure regulating vvalve is instantly altered. By interpolating the laminar resistance with the multiplicative correcting .factor B, a multiplicative volume alteration of the fuel supply is given which can be represented by the equation:

In this equation:

B is the amount of fuel; a is an additive correction factor; B is a multiplicative correction factor; 7 is a quadratic correction factor;

l is the air supply;

p is a proportionality factor.

The additional leminar resistance ensures that there is a large pressure drop at the equal pressure regulators than at the separate injection valves. Consequently, additional fuel is thus supplied to the injection valves, which corresponds to enrichment of the fuel mixture. Control of the valve can be effected by means of a contact connected to the throttle valve, for example with the throttle valve fully open.

On cold starting of the engine, a part of the fuel condenses on the cylinder walls and this leads to a fuelstarved mixture. In this case, action via the stop valve is possible by means of a temperature-dependent switch, which operates at lower engine temperatures. With a low engine temperature, this switch causes closure of the stop valve and then the fuel supply is increased multiplicatively over the whole operating range via the laminar resistance through the artificially increased pressure drop.

A further multiplicative effect for the purpose of altering the stoichiometrically desired fuel/air mixture is possible by itself or additionally by operation at the over-pressure regulator in the fuel control line leading back to the tank from the difference pressure regulator. According to a further feature of the invention, the mechanical force acting against the fuel force derived from a barometric pressure sensor bellows or a barometric pressure and temperature-sensitive bellows acts on the overpressure regulator and has its setting member connected with the membrane of the overpressure regulator. If the barometric bellows is filled with a gas under a predetermined pressure, then it reacts in the correct way tothe pressure and temperature variations of the atmosphere. In order to achieve a suitable spring constant in the bellows, an axially acting compression spring can be additionally arranged in this, if desired.

By means of the barometric bellows, the correction factor B in the above-mentioned equation is altered, whereby a multiplicative variation of the fuel supply results in such a sense that, with varying atmospheric conditions, such as during travel in winter with a warm engine or in mountain conditions, a correction of the mixing ratio tending towards a co-constant equal to zero is produced. j

A very simple possibility for additionally affecting the correction valve B is also possible by a specific construction of the amplifying resistance alone or of the amplifying resistance and the additional laminar resistance connected in parallel to the control valve. The laminar resistance can be in general advantageously consist, as where such resistances are usually used, of a sleeve or cylinder in which a piston is arranged, which consists of two axially spaced piston parts connected together by a rod having a diameter smaller than the internal diameter of the cylinder and forming an annulus between itself and the wall of the cylinder. To ensure a laminar flow, which is possible over wide limits, an annulas of approximately 80p. diameter has proved satisfactory. This laminar resistance can vary the multiplicative correction factor B, if the cylinder and the piston-rod-piston unit consist of materials with different coefficients of expansion. The coefficient of expansion of the material of the cylinder should be greater than i piston unit of steel. With decreasing temperature, the diameter of the gap forming the annular space becomes less and the pressure difference at the laminar resistance rises. This is therefore merely a correction factor, so that the alteration of the diameter of the annular gap has a magnitude of about a t.

According to a further feature of the invention, the resistance value of a laminar resistance can be adjusted in a simple way, by arranging a piston with one diameter somewhat larger than the other in a correspondingly widened cylinder bore and adjusting the length determining the resistance by shifting the piston-rod-piston unit in the sleeve.

It can also be desirable to make the enrichment of the fuel/air mixture independent of the load. This can be achieved, according to a further feature of the invention, by introducing a turbulent resistance with a quadratic characteristic upstream of the amplifying resistance in the fuel control line. This turbulent resistance can consist of a slotted disc. At a low fuel throughput, this turbulent resistance does not have any effect. If the fuel throughput increases, then its pressure drop rises quadratically, so that 'y in the above-given equation is increased correspondingly. The turbulent resistance, with increasing fuel throughput, thus additionally increases the pressure drop in the fuel control line downstream of the amplifying resistances, so that a greater supply of fuel to the injection nozzles is achieved.

With some engines, it is necessary to provide an additional additive fuel supply, particularly at low rates of revolution, e.g. on cold starting. This is achieved according to a further feature of the invention by connecting a by-pass conduit to the fuel control line upstream ofthe pressure regulating valve, in which bypass a regulating valve adjustable in dependence upon engine temperature is included, the by-pass being connected to the fuel control line downstream of the pressure regulating valve. Operation of the adjustable additively-acting regulating valve can be effected, for example, by means of a bi-metal regulator mounted on the engine and sensing its temperature. If the adjustable regulating valve is opened with the engine cold, an additional fuel control supplyflows through the by-pass conduit, and thus decreases the pressure in the'fuel control line between the amplifying resistance and the pressure regulating valve. Also, in this way, an enrichment of the fuel mixture is produced. The additivelyacting adjustable regulating valve modifies the value of a in the above-mentioned equation, for an additive mixture variation. It is satisfactory if the additivelyacting regulating valve is opened or closed continuously.

Another possibility arises for similarly additive operation on the air side of the device according to the invention. According to a further feature of the invention, in a by-pass connected round the valve plate, a preferably temperature-dependent member for modifying the by-pass cross-section is provided. This temperature-dependent member can also be adjustable by means of a bi-metal regulator mounted on the engine and sensing its temperature. Ifthe throughput in the bypass is decreased by means of the throttle member arranged in it, then the amount of air in the air measuring device increases correspondingly. Thus the fuel supply is also increased.

According to a further feature of the invention, an aperture in the valve plate provides a simple additive correction. This aperture, like the air by-pass, also produces a modification of the value of a in the abovementioned equation, namely an additive alteration of the relationship. According to a further feature of the invention, the size of the aperture in the valve plate is adjustable by means of a shutter plate. An alteration of the size of the aperture corresponds physically to a movement of the valve plate relative to the control member. By means of the aperture in the valve plate, both adjustment of the mixture for idle running and also additive enrichment of the mixture in idling can be obtained with a single setting member.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described below in conjunction with the embodiments illustrated in the accompanying drawings, wherein:

FIGS. 1 and 2 show two different forms of the device according to the invention:

FIG. 3 shows a device, for example according to FIG. 2, with the additional components enabling enrichment of the fuel/air mixture to be effected;

FIG. 4 shows a laminar resistance for the device according to the invention;

FIG. 5 shows a valve plate with an aperture adjustable in size;

FIG. 6 shows an air by-pass conduit effecting enrichment of the fuel/air mixture and connected across the valve plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment illustrated in FIG. 1, the fuel is pumped by a pump 1 from a tank 3 into a supply line 5. It then flows through a laminar amplifying resistance 7 and a line 9 to an air measuring device 11.

The air measuring device 11, which is arranged upstream of the throttle valve to be operated as desired, in the direction of flow of the air consists of a control cylinder 12 in which is arranged a control member 13 provided with an annular groove 14. The fuel control line 9 discharges in the region of the control cylinder in which the annular groove 14 is located. The fuel supplied from the fuel line 9 consequently fills the annular groove 14. The control cylinder 12 also includes a longitudinal slot 15 which is of rectangular cross-section and whose long axis runs parallel to the axis of the cylinder. The slot 15 is provided at a region where a control edge 17 of the control member 13 can cover the slot to a greater or lesser extent on inward and outward travel of the control member 13.

The throughput cross-section at the slot 15 is effectively dimensioned by the position of the control member 13. The amount of fuel which flows through the throughput cross-section of the slot 15 passes from its outlet side into a duct 21 which leads it to a first regulating chamber 23 of a difference pressure regulator 25. From the first chamber 23, the fuel can then flow through a duct 27 to an overpressure regulator 29, which prevents evaporation of the fuel. The fuel flowing through the overpressure regulator 29 then passes via a duct 31 back to the tank 3.

In the combustion air inlet channel 18, a valve plate 19 is located, which is secured to the control member 13. This valve plate 19 is contacted by the incoming combustion air, which exerts a pneumatic force upon it. This pneumatic force is constant, even if the valve plate moves in and out with the control member. During its inward and outward movement, only the amount of air flowing round theedge of the valve plate19 is altered. The pneumatic force acting on the valve plate'19 must be opposed by a counterforce which like the pneumatic force is constant. This counterforceis produced hydraulically by passing fuel under pressure into apressure chamber 35 adjacent the end face 20 of the control member 13, namely via a line 33 leading off from the duct 21 in FIG. 1. Since the pressure in the duct 21 is subjected to fluctuation, togetherwith the control pressure in thefuel control line 9, care must be taken that this fluctuating pressure, together withan additional spring 37 producing a counterforce, exactly counteracts the hydraulic and mechanical force according to the pneumatic force.

In theembodiment according toFIG. 2, thepressure space 35 is connected to the conduit leading from the difference pressure regulator to the overpressure regulator. Since the pressure in the duct 27 upstream of the overpressure regulator 29 is constant, the spring 37 can be dispensed with.

In the difference pressure regulator 25, the firstregulating chamber 23 is separated from the second chamber 41 by means of a membrane 39. The control pressure acts in the regulating chamber 41 and also acts in the fuel control line 9, since the second regulator chamber 41 is directly connected with the fuel control line 9 via the line 45. The magnitude of the force which the spring 43 exerts on the membrane 39 determines the difference pressure between the chambersand the fuel control line 9 and the line 21 at the outflow side of the control member. This ensures that the difference pressure is effective in controlling the size of the throughput cross-section .of the slot 15. I

In order to ensure that the correct overpressure acts in the pressure space 35 under all operating conditions, in the embodiment according to FIG. 1, an auxiliary duct 47 leads off from the fuel feed line leading to the injection valves, which duct 47 allows a small balancing flow to pass through a throttle valve 49, which passes via a duct 51 into the first regulating chamber 23 of the difference pressure regulator 25.

In the embodiment according to FIG. 2, an auxiliary duct 47 which allows a small balancing flow to pass through the throttle 49 can likewise be taken off from the line 5. The duct 51 discharges in this case, however,

into the duct 27 upstream of the overpressure regulator 29. The small balancing flow then passes into the pressure space of the overpressure regulator 29 and serves to improve the dynamic conditions there. Since the pressure in the duct 27 is constant, no special steps are necessary in this embodiment to ensure constant pressure in the space 35.

The fuel flowing through the components comprising the air measuring device 11, the difference pressure regulator 25, the overpressure regulator 29 and the throttle 49 serves solely and entirely for control purposes. Consequently, the fuel flowing in these parts of the device finally returns to the tank 3. In the device,

the control pressure is produced which controls the equal pressure regulator for the separate injection valves.

A further line 46 apart from the line 45 leads-off from the fuel line 9 and passes to further regulating chambers 52 which are in parallel to the second regulating chamber 41. The regulating chambers 52 are parts of 10 equal pressure regulators 53 which are connected in parallel with and associated with a fuel injection valve.

The fuel required to feed the injection valves is supplied via the line 5 which is provided with a branch connection in the regionof each equalpressure regulator 53. A laminar measuringresistance 55 is associated with each parallel branch and is disposed in a duct 57 which leads to the measuring chamber 59 of the respective pressure regulator 53. The measuring chambers 59 are separated from the regulating chambers 52 by means of membranes 61. The membranes'6l should have the least possible spring resistance. They can thus react sensitively to the fluctuations of the control pressure. The inlet opening 63 ofa duct 66 is located opposite the membrane 61. If the membrane 61 rises because of decreasing control pressure, then via the opening 63 more'fuel passes in the duct 66 to the injection valve. If, in contrast, control pressure rises, then the membrane6l falls and the opening 63 becomes more closed. Consequently the fuel supply to the injection valve is reduced. All associated equal pressure regulators operate in the same manner and in parallel with one another. 1

Equlibrium occurs when pressure in the measuring chamber 59 is equal to the pressure in the regulating chamber 52. Since this is produced continuously because of the compensatory effect of the membrane. the pressure drop at the amplifying resistance 7 must always remain exactly equal to the pressure drop at the measuring resistance 55. Consequently, the amount of fuel to be injected is determined precisely and is exactly proportional to the amount of air flowing through the combustion air channel.

The measuring resistance of the separate pressure regulators 53 have no effect either upon the control flow or, therefore, upon the control pattern. For this reason, any number of pressure regulators and measuring resistances can be connected in parallel without the accuracy of measurement being affected. I

A magnetic valve 65 is installed in the feed line 5 upstream of the first branch line to a pressure regulator 53, This magnetic valve 65 has the purpose of cutting off the fuel supply to the separate pressure regulators on skidding or other uncontrolled movement.

The amount of fuel supplied is independent of the injection pressure at the injection nozzles. The throughput amounts in the lines 9 and 21 depend upon the measurements of the slot or throughput opening 15. In the difference pressure regulator 25, a membrane 39 separates the pressure space 23 from a pressure space 41. The magnitude of a force which is exerted by a spring 43 on the membrane 39 thus determines the difference pressure remaining constant in value between the pressure spaces 23 and 24 or the difference pressure between the fuel in the lines 9 and 21, respectively. For this purpose, the chamber 41 is connected to the fuel control lines 9 via the line 45.

A line 46 parallel to the line 45 is likewise connected with the pressure spaces 52 of the pressure regulator 53. In these pressure regulators, a membrane 61 separates the pressure spaces 52 from the pressure spaces 7 In the fuel control line 9, a valve 67 is arranged downstream of the amplifying resistance 7 and is connected in parallel to a laminar resistance 7a. The valve 67 is remotely controllable, via the accelerator pedal 68 with a switch 69 and also via a bimetal switch 70a associated with the engine 70. By means of the accelerator pedal 68, the valve 67 is actuated as an on/off valve and is closed when the accelerator pedal 68 is substantially completely depressed. In the fully depressed position of the pedal 68, which corresponds to the throttle valve being fully open, the pedal 68 actuates the switch 69 which causes closure of the valve 67. Thus the additional laminar resistance 7a is connected into the fuel control line 9 and thus decreases the pressure in the fuel control line 9. The reduction of the pressure operates multiplicatively so as to produce an enrichment of the fuel/air mixture so that, with the pedal 68 fully depressed, the load on the engine can be increased. The bimetal switch 79a likewise controlling the valve 67 is arranged directly on the engine 70 and records its temperature. With a cold engine, it closes the valve 67 so that enrichment occurs with cold starting. Both with full depression of the pedal 68 and also on switching on the valve via the bimetal strip 70a, the multiplicatively operating correction actor B modifies the fuel/air relationship.

The multiplicative alteration of the amount of fuel supplied to the air can also be achieved in a similar way by a barometric bellows 71 which acts upon the membrane of the over-pressure regulator 29. The barometric bellows 71 can be filled with a gas ofa suitable pressure and composition so that it regulates the gas mixture on pressure and temperature alterations, whether during travel on mountain roads or during winter use and so on, such that the co-content is as near to zero as possible. The multiplicative variation of the amount of fuel contained in the fuel/air mixture can be readily adjusted to any satisfactory value by means of this barometric bellows acting on the over-pressure regulator. Presetting of the barometric bellows can be effected with the aid of a compression spring 73 acting in the direction of expansion ofthe bellows.

In FIG. 4, a laminar resistance is illustrated which is adjustable in magnitude and is also temperature dependent. This laminar resistance consists of a cylinder 171 in which a unit consisting of a piston-173, a piston rod 175 and a second piston 177 is axially movable. The pistons 173 and 177 are fitted in the cylinder in a fluidtight manner. The external diameter of the piston 177 is slightly greater than the internal diameter of the cylinder part 171 in which the piston 173 is arranged. The piston rod 175 has an outer diameter only slightly less than that of the cylinder wall 181 which surrounds the cylindrical surface 183 of the rod 175. Between these wall surfaces 181 and 183, an annular gap 191 is thus formed having a diameter (radial dimension) of the order of 80a.

The two pistons 173 and 177 are bored through. Fuel can flow into and out of the borings 185 and 185'. Transverse channels 187 and 187' pass to annular grooves 189 and 189 from the internal ends of the borings 185 and 185. Via one annular groove 189, the fuel flows into the annular gap 191 representing a laminar flow section and, through the other annular groove 189', the fuel then flows out via the transverse channels 187 and the boring 185'.

The cylinder 171 is longer than the piston-rod-piston unit. Consequently, this unit is axially movable in the cylinder 171. Because of this ability to move, the resistance in the annular gap 191 forming the laminar section can be altered. The throughput length for the fuel between the left-hand annular groove 189 and the transition into the cylinder part with the greater internal diameter, namely the shoulder 193 in the righthand of the laminar resistance, thus determines the magnitude of the laminar resistance. If the correction by the bellows 71 is replaced by correction of temperature errors, then the errors, which arise through temperature alterations and the alteration of the air density connected therewith, can be compensated for by this laminar resistance, if the cylinder and the piston-rod-piston unit consist of two materials having two suitably different coefficients of thermal expansion. As the material for the cylinder, brass is a suitable example for instance, whereas the piston-rod-piston unit can preferably be made of steel. It will also be clear that other combinations of metals can be chosen. If the outer temperature drops, for instance, the density of the air rises. The fuel/air mixture thus becomes weaker in this way. Correction is then possible in that the different coefficients of expansion reduce the annular gap between the rod and the cylinder. Thus the pressure in the control lines 9, 45 and 46 drops and more fuel is injected in. By the changing laminar resistance, the correction factor B for multiplicative variation of the fuel/air mixture is thus modified.

A turbulent resistance 75 illustrated in FIG. 3, which is constructed as an apertured plate, can be used as another possibility available for varying the amount of fuel with respect to the amount of air. This turbulent resistance is substantially without effect, so long as the flow of fuel through it is small. If the fuel throughput rises, its pressure drop increases quadratically. Correspondingly, with increasing throughput values, the pressure in the fuel control line 9 drops. By means of the turbulent resistance 75, strengthening or enrichment of the fuel/air mixture with large amounts of fuel can be carried out in dependence upon the applied load.

An additive enrichment and thus an additional correction to the correction value a can be particularly desirable for cold starting. This additive enrichment can be effected by means of a by-pass line 77 in which a regulating valve 79 is arranged. This regulating valve is controlled by means of a bimetal regulator b which is arranged on the engine 70. With the engine cold, the regulating valve 79 is opened and it closes increasingly with increasing engine temperature. By the inclusion of the by-pass line 77 between the fuel control line 9 and the line 21 returning to the tank downstream of the pressure regulating valve 11, with the engine cold, :1

part of the fuel flows via the line 21 to the valve 11, so that the pressure in the fuel control line is decreased. With decreasing pressure in the fuel control line. however, the pressure drops at the pressure regulators 53 thus increase so that the throughput openings 63 become more open.

With an alteration of the valve plate 19 according to FIG. 5, a further additive regulation of the mixing ratios of fuel and air can be effected. An aperture 81 is provided in the valve plate 19 and, by means of a shutter member 83 pivotally mounted at 85, this aperture can be closed to a greater or lesser extent. Alteration of the cross-section of the aperture is physically equivalent to moving the valve plate 19 on the control member 13.

By means of this movement, an idling mixture adjustment can be carried out. The same effect can be achieved if the shutter plate 83 is adjusted to the desired extent and is then held in place by means of a screw 87 arranged at the pivot point 85.

By means of the aperture 81 in the valve plate and the shutter plate 83, the mixture can be adjusted for idling running. With increased closure of the aperture 81, additive enrichment of the mixture on idling increases. By means of the plate 83 alone, both idling mixture adjustment and also enrichment of the mixture during idling can thus be regulated.

In the same way as enrichment of the mixture can be effected by varying the air side, by the aperture 81 in the valve plate 19, an alteration at the air side can also be made by means of an air by-pass 89 illustrated in FIG. 6, which goes past the valve plate 19. In the air bypass, an adjustable throughput cross-section 91 is provided, which can be regulated also by means of the bimetal regulator 70a or 70b. The bi-metal regulator measures the engine temperature and thus opens the air by-pass 89 as the engine temperature rises.

All correction members incorporated in the device alone or in combination effect and providing for the most varied starting conditions control of the engine under all operating conditions, the additional laminar resistance 7a and the barometric bellows 71 producing a multiplicative correction factor B, the turbulent resistance 75 producing a quadratic correction factor y and the regulating valve 79 as well as the aperture and and the by-pass 89 producing an additive correction factor or modifying the mixture vary the fuel/air volume relationship in accordance with the abovementioned equation. The means used are ofa simple kind and can be installed in the apparatus without major expense.

We claim: I

1. An apparatus on internal combustion machines with a device for continually measuring the amount of incoming combustion air and for measuring and uniformly distributing the amounts of fuel corresponding to the amount of air to a plurality of injection valves associated with a plurality of operating cylinders, wherein a measuring device exposed to the combustion airstream is arranged in the air inlet channel which alters a throughput opening in a fuel control line in proportion to the amount of air flowing in the inlet channel, whereby, in the fuel control line connected upstream to the fuel pump via an amplifying resistance, conveying a fuel control flow and connected downstream via a difference pressure regulator back to the tank, there is produced a fuel control pressure downstream of said amplifying resistance which fuel control pressure actuates a plurality of pressure regulators connected in parallel and associated with the respective injection valves, through which the fuel passes via measuring resistances for injection and in which the outflow cross-section is adjusted in dependence upon the fuel control pressure so that the pressure drop at the measuring resistance of each pressure regulator is equal to the pressure drop at the amplifying resistance.

2. An apparatus according to claim 1, in which the throughput opening is provided in a control cylinder in which the measuring device is arranged to move a control member provided with an annular groove, one wall of the annular groove serving as a control edge determining the throughput cross-section,

-3. An apparatus according to claim 1, in which the fuel measured at the throughput cross-section passes into a first regulating chamber of the difference pressure regulator, which is separated by means ofa membrane from a second regulating chamber subject to the control pressure, and in which a force acts against the membrane from the side of the first regulating chamber which determines the difference pressure between the regulating chambers and serves to control the throughput cross-section.

4. An apparatus according to claim 3, in which the fuel supplied to the first regulating chamber returns to the tank via an overpressure regulator.

5. An apparatus according to claim 1, in which a fuel line connected upstream of the amplifying resistance passes fuel supplied from the pump via a throttle to the first regulating chamber and an additional compensat' ing flow thus passes to the overpressure regulator arranged in the return line to the tank.

6. An apparatus according to claim l'in which a pressure space is provided in the control cylinder on the side downstream from the measuring device which is represented by a valve plate and is defined by the end surface of a control member remote from the valve plate, the pressure space being connected to one of the inlet ducts which supplies fuel under pressure.

7. An apparatus according to claim 6, in which the pressure space is connected to the fuel line downstream of the throughput opening.

8. An apparatus according to claim 6, in which the pressure space is connected to a duct supplying constant pressure fuel between the difference pressure regulator and the overpressure regulator.

9. An apparatus according to claim 1, in which a fuel line is taken off upstreamof the amplifying resistance, from which parallel ducts provided with measuring resistances are connected to the measuring chambers of the pressure regulators.

10. An apparatus according ,to claim 1, in which the pressure regulator includes a regulating chamber under,

the-control pressure and a measuring chamber separated by means of a membrane from this chamber, in which measuring chamber a valve is located which opens or closes to a greater or lesser extent according to the magnitude of the flexing of'the membrane controlled by the control pressure.

11. An apparatus according to claim 1, in which the amplifying resistance and the measuring resistances are laminar resistances.

12. Apparatus according to claim 1, in which in the fuel supply line common to the pressure regulators and feeding the injection valve arrangement, a magnetic valve is provided.

13. An apparatus according to claim 1, in which, in the fuel control line downstream of the amplifying resistance, a remotely-controlled closure valve is arranged which is connected in parallel with a laminar resistance.

14. An apparatus according to claim 1, with an overpressure regulator in the fuel control line leading from the difference pressure regulator to the tank, in which a mechanical force acts upon the overpressure regulator against the fuel force, which is derived from a barometric pressure bellows or a pressure and temperaturesensitive barometric bellows, whose setting member is connected with the membrane of the overpressure regulator.

15. An apparatus according to claim 1, in which the amplifying resistance alone or together with the additional laminar resistance connected in parallel with the closure valve comprises a cylinder in which a unit is located which consists of two axially-spaced pistons connected by means of a rod whose diameter is smaller than the internal diameter of the cylider so that an annular gap is formed between it and the cylinder.

16. An apparatus according to claim 15, in which the annular gap has a diameter which causes laminar flow, for example about 80p 17. An apparatus according to claim 15 in which the cylinder and the piston-rod-piston unit consist of materials of different coefficients of expansion.

18. An apparatus according to claim 15 in which the coefficient of expansion of the material of the cylinder is greater than that of the piston-rod-piston unit.

19. An apparatus according to claim 15 in which the cylinder is brass and the plston-rod-piston unit is steel.

20. An apparatus according to claim 15 in which one piston with a greater diameter than the other is provided with a correspondingly widened cylinder boring and the piston-rod-piston unit is movable in the longer cylinder section.

21. An apparatus according to claim 1, in which a bypass duct is connected to the fuel control line upstream of the pressure regulating valve, in which a regulating valve adjustable in dependence upon the engine temperature is located and which is again connected to the fuel control line downstream of the pressure regulating valve.

22. An apparatus according to claim 1, in which an aperture is provided in the valve plate, where the size of the aperture is adjustable by means of an adjustable shutter plate. 

1. An apparatus on internal combustion machines with a device for continually measuring the amount of incoming combustion air and for measuring and uniformly distributing the amounts of fuel corresponding to the amount of air to a plurality of injection valves associated with a plurality of operating cylinders, wherein a measuring device exposed to the combustion air-stream is arranged in the air inlet channel which alters a throughput opening in a fuel control line in proportion to the amount of air flowing in the inlet channel, whereby, in the fuel control line connected upstream to the fuel pump via an amplifying resistance, conveying a fuel control flow and connected downstream via a difference pressure regulator back to the tank, there is produced a fuel control pressure downstream of said amplifying resistance which fuel control pressure actuates a plurality of pressure regulators connected in parallel and associated with the respective injection valves, through which the fuel passes via measuring resistances for injection and in which the outflow cross-section is adjusted in dependence upon the fuel control pressure so that the pressure drop at the measuring resistance of each pressure regulator is equal to the pressure drop at the amplifying resistance.
 2. An apparatus according to claim 1, in which the throughput opening is provided in a control cylinder in which the measuring device is arranged to move a control member provided with an annular groove, one wall of the annular groove serving as a control edge determining the throughput cross-section.
 3. An apparatus according to claim 1, in which the fuel measured at the throughput cross-section passes into a first regulating chamber of the difference pressure regulator, which is separated by means of a membrane from a second regulating chamber subject to the control pressure, and in which a force acts against the membrane from the side of the first regulating chamber which determines the difference pressure between the regulating chambers and serves to control the throughput cross-section.
 4. An apparatus accoRding to claim 3, in which the fuel supplied to the first regulating chamber returns to the tank via an overpressure regulator.
 5. An apparatus according to claim 1, in which a fuel line connected upstream of the amplifying resistance passes fuel supplied from the pump via a throttle to the first regulating chamber and an additional compensating flow thus passes to the overpressure regulator arranged in the return line to the tank.
 6. An apparatus according to claim 1 in which a pressure space is provided in the control cylinder on the side downstream from the measuring device which is represented by a valve plate and is defined by the end surface of a control member remote from the valve plate, the pressure space being connected to one of the inlet ducts which supplies fuel under pressure.
 7. An apparatus according to claim 6, in which the pressure space is connected to the fuel line downstream of the throughput opening.
 8. An apparatus according to claim 6, in which the pressure space is connected to a duct supplying constant pressure fuel between the difference pressure regulator and the overpressure regulator.
 9. An apparatus according to claim 1, in which a fuel line is taken off upstream of the amplifying resistance, from which parallel ducts provided with measuring resistances are connected to the measuring chambers of the pressure regulators.
 10. An apparatus according to claim 1, in which the pressure regulator includes a regulating chamber under the control pressure and a measuring chamber separated by means of a membrane from this chamber, in which measuring chamber a valve is located which opens or closes to a greater or lesser extent according to the magnitude of the flexing of the membrane controlled by the control pressure.
 11. An apparatus according to claim 1, in which the amplifying resistance and the measuring resistances are laminar resistances.
 12. Apparatus according to claim 1, in which in the fuel supply line common to the pressure regulators and feeding the injection valve arrangement, a magnetic valve is provided.
 13. An apparatus according to claim 1, in which, in the fuel control line downstream of the amplifying resistance, a remotely-controlled closure valve is arranged which is connected in parallel with a laminar resistance.
 14. An apparatus according to claim 1, with an overpressure regulator in the fuel control line leading from the difference pressure regulator to the tank, in which a mechanical force acts upon the overpressure regulator against the fuel force, which is derived from a barometric pressure bellows or a pressure and temperature-sensitive barometric bellows, whose setting member is connected with the membrane of the overpressure regulator.
 15. An apparatus according to claim 1, in which the amplifying resistance alone or together with the additional laminar resistance connected in parallel with the closure valve comprises a cylinder in which a unit is located which consists of two axially-spaced pistons connected by means of a rod whose diameter is smaller than the internal diameter of the cylider so that an annular gap is formed between it and the cylinder.
 16. An apparatus according to claim 15, in which the annular gap has a diameter which causes laminar flow, for example about 80 Mu .
 17. An apparatus according to claim 15 in which the cylinder and the piston-rod-piston unit consist of materials of different coefficients of expansion.
 18. An apparatus according to claim 15 in which the coefficient of expansion of the material of the cylinder is greater than that of the piston-rod-piston unit.
 19. An apparatus according to claim 15 in which the cylinder is brass and the piston-rod-piston unit is steel.
 20. An apparatus according to claim 15 in which one piston with a greater diameter than the other is provided with a correspondingly widened cylinder boring and the piston-rod-piston unit is movable in the longer cylinder section.
 21. An apparatus according to claim 1, in wHich a by-pass duct is connected to the fuel control line upstream of the pressure regulating valve, in which a regulating valve adjustable in dependence upon the engine temperature is located and which is again connected to the fuel control line downstream of the pressure regulating valve.
 22. An apparatus according to claim 1, in which an aperture is provided in the valve plate, where the size of the aperture is adjustable by means of an adjustable shutter plate. 